Measurement of platelet-derived microparticle levels in the chronic phase of cerebral infarction using an enzyme-linked immunosorbent assay.

Assessment of platelet function is a critical component of the treatment and secondary prevention of cerebral infarction, and measurement of platelet-derived microparticle (PDMP) levels using flow cytometry may be a good indicator of platelet function. However, the flow cytometric analysis is not feasible in a variety of clinical situations. The goal of the present study was to measure PDMP levels using an enzyme-linked immunosorbent assay (ELISA) in chronic cerebral infarction patients and to determine the utility of PDMP level measurement for the monitoring of the effect of cilostazol and aspirin. A crossover study was performed using 4-weeks of aspirin (100 mg/day) and 4-weeks of cilostazol (200 mg/day) in 18 patients. PDMP levels were also measured in 20 volunteers as controls. Experiments demonstrated that PDMP levels were significantly higher in chronic cerebral infarction patients (median 8.8 U/ml, interquartile range 5.1-14.9 U/ml, n=18) than in controls (median 5.5 U/ml, interquartile range 5.0-8.2 U/ml, n=20) (P=0.047). PDMP levels did not decrease after therapy with either aspirin (median 10.9 U/ml, interquartile range 6.2-17.9 U/ml, n=12) or cilostazol (median 9.2 U/ml, interquartile range 6.1-14.3 U/ml, n=12) compared with baseline PDMP levels in the 12 patients who completed this trial (median 11.4 U/ml, interquartile range 5.2-23.7 U/ml, n=12). There were no significant differences in PDMP levels between aspirin and cilostazol (P=0.61). In conclusion, PDMP levels as measured by ELISA were increased in patients with chronic cerebral infarction regardless of the anti-platelet therapy. This methodology may be a useful strategy of assessing platelet function in chronic cerebral infarction patients.